LIGHTNING

Background Information

• Lightning occurs about 2000 times at any one moment.

• Thunderstorms thrive under certain conditions. The two most basic

elements that cause a thunderstorm to develop are:

– Moisture

– Rapidly rising warm air

• A lightning flash is composed of a series of strokes with an average of

about four. The length and duration of each lightning stroke vary, but

typically average about 30 microseconds. (The average peak power per

stroke is about 1012 watts). Occurs when the air can’t insulate the

charges any longer.

• When the potential becomes great enough, electricity punches its

way through air that normal insulates, and builds a narrow bridge of

electrified gas or plasma.

• The current burrows its way in search of an oppositely charged

region where the imbalance can be relieved. When the two are

joined, current flows freely and ionizes even more air on its path,

thus creating the glowing hydra that we see as a lightning bolt.

• NCAR found that clouds become electrified only after significant amounts of ice particles and supercooled water form at heights above the freezing level.

• Negative cloud charge tends to develop in cells or blobs, rather than the uniform layers previously theorized.

Lightning Bolts

• Happens in a series of stages. First, a faint step leader emerges from the base of the cloud,

moving towards the ground in steps of 50 meters or so. Branching as it goes down, which is

why so many lightning bolts "fork".

• As the step leader nears the ground, it attracts "streamers" of positive charge from the

ground. When it finally connects with one of these streamers, a brilliant return stroke occurs

as the charge drains out of the ionized path. The return stroke travels upwards as the ground

charge goes first. This process can be repeated up to 40 times, which is why so many seem

to flicker.

Some chemistry about lightning

• When lightning occurs, sometimes you can smell it.

Intense heat & electrical current produce mini-chemical

factory where O2 and N2 are broken down into ions.

Some reform into O2 and N2 but a significant number

form Nitrous oxide compounds.

• O2 + N2

electric current + intense heat from lightning

NO , NO2 , NOx

O2 + N2

• In the 1983 Global Troposphere Experiment, aircraft sampled the air

inside two cumulonimbus clouds and found that the levels of NO

had risen 50-fold, from 20 to 1000 parts per trillion.

• If this proves to be true

of all thunderclouds, then

lightning especially cloud-to

-cloud flashes closer to the

stratosphere could be a

significant producer of

chemicals that deplete the

Earth's protective ozone

layer.

Theories

• Scientists know that lightning occurs due to a separation of charged

particles, but the mechanism behind acquiring the charges still

remains unknown. There are a variety of theories which have been

put forward.

• The theories are:– Cosmic particles bombarding the atmosphere from space

– Dust particles rubbing against each other– Large particle, small particle updraft theory (ICE)

– Electro-release condensation theory

Cosmic Particle Theory• Some scientists suggest lightning is

the result of cosmic particles coming

from space

• Least respected/documented theory

If this were the case, why don’t we see an

increase in the frequency of lightning at

solar maximum, a decrease at solar

minimum, or just an overall fluctuation in

lightning frequencies?

Dust Particle TheorySome scientists suggest that dust particles

from volcanic eruptions, forest fires or human

induced pollution create this potential for

lightning, by bumping into each other then

separating the charged particles.

If this were the case we would be able to see

a marked increase in storm intensities when

dust particles interacted with cloud nuclei.

But dust particles do influence the type of

lightning as discussed later concerning

positive cloud to ground strikes.

Ice Theory• The most accepted view of how charge separation occurs…but not

necessarily right.

• Water cycle. Clouds can suspend millions of water/ice particles.

• Collisions with other particles due to evaporation/condensation.

• Electrons knocked off rising moisture - Collect at the bottom as positive

moisture particles rise above them by strong updrafts

• As moisture particles get higher, begin to freeze – giving them negative

charge and then fall back down to earth.

• The problem with this is that storms that contain no ice still produce lightning

so their must be something else going on which explains why lightning

occurs, although it still has to do with the water cycle.

Electro – Release Condensation

• NASA has shown that there is a correlation between the

volume of rain in a storm and the amount of lightning.

• Although not established fact, it does fit the parameters

for lightning.

• The theory is based on the Mills Law of Electron

Transfer Via Matter State Changes.

Mills Law of Electron Transfer Via Matter State Changes

• States that when matter changes states, there will be a

corresponding transfer of electrons.

• Predicts condensing areas have negative areas or surplus of

electrons.

• Dissipating parts due to evaporation will have positive charge and

loss of electrons.

• Freezing/thawing.

• Volume + rapidity of condensation determines the amount of

lightning produced.

The Chemistry Of This• Water molecules in liquid state share electrons

covalently enabling H2O molecules to exist at a lower

energy level, the factor making them behave as a liquid.

• H2Oliq + heat locks up e- in complete outer sub shell.

• Molecule now free to act as a gas & refuses to share

electrons, leaving behind fewer electrons to be shared

by the rest of liquid water.

The Chemistry Continued.

• As the gas H2O lose heat energy, also lose ability to

maintain full outer shell of e-

• Gas molecules forced to condense with each other,

sharing e-

• Giving up surplus of heat & e- can no longer afford to

hold.

• If condensation occurs quick + sufficient enough, a

lightning storm will ensue.

• Research by two separate teams, Studwell and Orville (1995) and

Holle and Watson, (1996) discovered a majority of positive flashes,

in areas of freezing rain. As water freezes it becomes negatively

charged. Since freezing rain becomes frozen on contact with the

ground, it imparts a negative charge to the ground on freezing. Any

discharge would be a positive flash!

• Laboratory experiments directed by E J Workman at the New

Mexico Institute of mining and technology back up the freezing rain

theory by showing that when dilute solutions of water are frozen, a

large electric potential develops between the water and the ice. The

experiments show that the ice gains a negative charge while the

water retains a positive charge. Again exactly what the theory of

Electron Transfer Via Matter State Change predicts.

Evidence For The Theory

Summary• Expect more storms on the plains + southern states of

U.S where potential for large amounts of moisture can

rise to great heights and cooled quickly, hot & cool air

collide.

• NW U.S and Canada plenty of moisture but not warm

enough, so condensation has chance to bleed off

resulting in drizzle with few storms.

• Explains all the observable results shown by

experiments

Houston, Lightning Capital of Texas

• 12 year study by Texas A&M concluded that lightning strikes Houston more than anywhere else.

• 4-5 million people in area plus 50% petroleum refineries in U.S create massive heat island.

• Results in increased cumulous clouds formation and more intense storms.

• 1.6 million cloud-to-ground flashes with 75% during summer

Other Facts from Houston

• Air pollution considered a factor relating to lightning

frequency. Affecting the mix of water and ice in a

thunderstorm which affects the charging process.

• Also aerosols from urban areas may increase the flash

density which has been observed in Houston area.

Florida Scientist’s Research

• According to Joseph Dwyer, physics Prof. at Florida tech. conditions

we thought necessary for lightning do not occur in nature.

• For generations we thought that the electric fields must be

enormous to create such a charge.

• Scientists have been searching for these for years but come up

empty handed.

• Not looking hard enough? No just don’t exist.

• New limit in nature, like water in a bucket, stunted by gamma rays

and anti-matter positrons.

Lightning and Tornadoes?• When scientists from a dozen universities + instruments took to a corn field

on the Kansas/Colorado border they came up with some surprising results.

• Most importantly, researchers witnessed several events within storms that

seemed to predict when tornadoes form. They noticed several updraft areas

where lightning would suddenly cease, then seconds later, a tornado would

form.

• Importance of this is better prediction by weather-forecasters for severe

weather. Use of instruments to collect data on positive strikes - special radar

stations

• Apart from their results on positive cloud to ground strikes which I

will discuss in a minute they found new clues which might explain

strange lights observed in upper atmosphere above clouds called

red sprites, blue jets, trolls and elves.

• Sprites which can be

seen by naked eye are

glowing ribbons which rise high

above blue jets, last for 3-10 milli.

secs. But they only occur over

positive cloud to ground strikes.

A Sprite can exceed 10 million meters a second

Blue Jets• Blue jets are extremely energetic fields of charged

particles that rise up to 30 miles from the tops of clouds. After they occur, lightning stops for several seconds.

• These are very rare and not much

is known about them but they can

reach speeds of 100,000 metres

a second.

Positive Cloud to Ground Strikes

• In a positive-to-ground lightning strike, positive charges first rush from the

cloud to the ground, creating a lightning channel through which electrons

flow from the ground back up to the cloud. Such lightning strikes tend to

carry more charge, last tens of seconds longer and be less branched than

the more common negative-to-ground lightning.

• The presence of smoke, dust, or pollution seems to encourage the

development of positive flashes. This is probably because of the particles'

effect on the number and sizes of ice crystals within storms. A study in the

journal Science (10/2/98) examined thunderstorms in the Southern Plains

during the spring of 1998, when smoke from Mexican forest fires was

flowing northward over the region. Up to three times the usual number of

positive flashes were observed in these smoke-altered storms.

Pavel Jungwirth Paper• Too much info but basically their work was on how different compounds

affect the polarity of lightning strikes. • Under normal conditions, when sulfates dominate as cloud condensation

nuclei, this ionic mechanism is consistent with the prevailing negative lightning in thunderstorms. But with the decrease of sulfate anions, the present mechanism predicts a shift towards positive charging. This fits well to a large range of observations of enhanced positive lightning, connected with smoke, rich in chlorides and nitrates, that could not be previously explained.

• Performed tens of such collision simulations, have always observed transfer of several to several tens of water molecules, 1-8 ammonium cations, and 0-3 sulfate dianions from the graupel (snowflake crystals falling through very moist air) to the ice crystal. In all cases, the number of transferred ammonium cations was larger than twice the number of sulfate dianions. Consequently, these collisions led to positive charging

of the ice crystal (and negative charging of the graupel).

Links to Aerosols and Forest Fires• Under certain atmospheric conditions (biomass burning

or forest fires) a large amount of aerosols containing

other soluble ions, such as potassium cations and

chloride and nitrate anions are released into the

atmosphere.

• The present simulations indicate that replacing the

sulfate dianion with monovalent anions such as chloride

or nitrate leads to an opposite polarity of charging during

graupel-ice crystal collisions, due to the change in the

salt solution covering the graupel.

• The fires in the south of Mexico in 1998 accumulated for a tripling of positive lightning over the U.S. The median peak current was increased by over 20 kA. Chemical analysis of the smoke that reached the USA, showed that the fraction of nitrate and organic anions was greater than in the ambient aerosols.

• A very clear signal was also obtained from cumulimbus clouds fed directly from forest fires in the USA and Canada. Latham (1991) documented that a large prescribed fire in Canada caused a pyrocumulus storm that had produced exclusively 21 positive cloud to ground flashes, whereas other thunderclouds in the vicinity that did not ingest the smoke produced tens of “normal” negative flashes.

• Canadian scientists suggested positive lightning was responsible for the fires because of their higher energy and they persist longer. Positive feedback loop.

NASA Discoveries• Lightning prefers afternoons, believed due to the

land absorbing heat and causing strong convection.

• Patterns change each year, tremendous variations outside the tropics. As summer progresses in N Hemis. Lightning moves further north.

• Strong updrafts which cause lightning relate to stronger storms, predictions on type of storm.

• C-C lightning more energetic than C-G more likely to produce violent storms.

This map depicts the ratio of cloud-to-cloud lightning to cloud-to-ground lightning over U.S. The red areas show where the ratio is as high as 10 cloud-to-cloud strikes for every ground strike. Blue areas indicate ratios as low as 1:1. red predicted to be more energetic/violent

Benefits of Lightning

• This last section is something I found that links lightning strikes to health, but in a good way.

• After a storm, the air feels clean and fresh, filled with negative ions. In a thunderstorm, positive ions precede a strike, followed by negative ions after it.

• The air we breathe contains both + & - ions, a lack of or imbalance

of these ions has been proven to affect us and our environment.

• Research shows that most of us who live, work and travel in closed

spaces suffer some degree of negative ion starvation or positive ion

overabundance. This has become extremely evident to NASA in

their space travel program.   

• In cities like New York, Los Angeles, Hong Kong, Tokyo and Mexico

City and many densely populated cities, there may be few or no

detectable negative ions at all during heavy traffic and high pollution

periods.

• The natural production of ions may result from solar or cosmic

radiation or the more mundane friction between air masses such as

between rapidly moving hot, dry air and the ground. These are the

"Witches Winds" that cause such discomfort periodically to the

population in certain areas of the world.

• In these areas, the seasonal winds have become legendary,

bringing misery and chaos to many of the local people. In these

places it has been known for generations, that the winds bring

feelings of anxiety, stress, depression and sleepless nights.

• Statistics show that when they blow, more road accidents happen

and suicide rates increase.

• So real is the problem that it has been known for judges to take this

into consideration when sentencing, and for hospitals to postpone

some operations until the winds cease!  

Winds of Depression

The Ion Effect• There are some amazing clues to how an excess of

positive ions and a lack of negative ions can produce

uncomfortable effects, Studied by the Dr. Albert Krueger,

Professor Emeritus of the University of California at

Berkeley.

• Dr. Krueger demonstrated that small air ions are

biologically active and can stimulate the over-production

of the powerful neurotransmitter serotonin. Serotonin is a

very active neurohormone causing profound nerve,

glandular and digestive effects throughout the body.

• Negative ions can provide major benefits for asthma,

chronic fatigue syndrome, hay fever, allergies, sleep &

snoring, depression, sinus, migraines, colds & flu,

nausea, chemical sensitivity, cigarette smoke & other

odors, computers & office pollution. 

• The earth's atmosphere is absolutely full of ions. Nature

was making them even before life began.

• Western scientists believe that ionization, in the form of

lightning, was probably instrumental in the formation of

amino acids - essential components for the beginnings of

life! 

Conclusions / What I have learnt• Non sulfate particles affect the amount of

+ive lightning strikes.

• Sprites + Jets

• Links to tornado/weather prediction

• Limitations of electric field size in the atmosphere.

• Urban heat affect, increases convection of cool air with warm air.